SPECIFICATION Scale: Inch scale Material: Aluminum and steel Boring size: 1/4", 3/8", 5/16", 7/16", 1/2". Bushing Set: Two each of 1/4", 5/16" and 3/8". Package include: Self Centering Dowelling Jig x 1, 5/16" Drill Sleeve x 2, 3/8" Drill Sleeve x 2, 1/4" Drill Sleeve x 2, "L" Type Wrench x 2. ERROR ADJUSTMENT METHOD Use a hexagon socket to loosen the two hexagon screws in the middle of the fixture.Adjust the aluminum alloy splints on the left and right sides of the central axis to make the left and right diameters of the splint consistent.Tighten the two hexagon socket screws with a hexagon socket.After debugging, the left and right distances are the same and the error is eliminated. FEATURES Accurate Self-centering By rotating the locking threaded rod, the aluminum alloy splints on both sides can be gathered or separated at the same time, realizing the accurate self-centering function. Wide Clamping Range The self centering dowelling jig plus can hold workpieces from 0.4'' to 2.4''. Accurate Positioning of Drilling Holes Quickly and accurately locate where you want to drill, saving your work time. Hardened Steel Drill Sleeve The set provides six hardened steel threaded sleeves, two for each of 1/4'', 5/16'' and 3/8''. SLIIMU is a brand of our company, dedicated to the design and production of hardware products, auto parts and other products. The products are made of high-quality raw materials. After many tests and adjustments, the quality is guaranteed and is loved by consumers. In the face of rampant low cost and poor quality piracy, we still stick to our original intention to make quality products worthy of your purchase cost. SLIIMU brand products are your wise choice. SLIIMU is a brand of our company, dedicated to the design and production of hardware products, auto parts and other products. The products are made of high-quality raw materials. After many tests and adjustments, the quality is guaranteed and is loved by consumers. In the face of rampant low cost and poor quality piracy, we still stick to our original intention to make quality products worthy of your purchase cost. SLIIMU brand products are your wise choice.